The present invention relates to a technology on use of a storage device (such as a disk array system, a hard disk, a tape library system or an optical disk library unit) in an information processing system, and more particularly to the technology on the use of a plurality of storage devices having respective characteristics in a plurality of controllers (computers).
As a technology arranged so that a plurality of computers (controllers) may share a storage device, today, a storage area network is widely used. Before the storage area network, it is not considered that the file system software running in the computer system is arranged so that a plurality of computers may share one storage device. In a case that such file system software is shared in the storage area network environment, the data (information) recorded in the storage device may be lost. U.S. Pat. No. 5,950,203 describes the technology of overcoming this shortcoming.
The foregoing prior art, however, discloses the technology on how a plurality of computers may share the storage device, while it does not disclose the way of using the storage system if the storage devices have respective attributes (performance, reliability, conservation, cost per one capacity unit, and so forth).
In this respect, the white paper of Tivoli Systems Inc. xe2x80x9cVision, Tivoli Storage Management Solutions for the Information Gridxe2x80x9d introduces the technology on storage of data as using the storage devices with their respective attributes in a storage area network. Even this white paper, however, does not disclose the method of managing the attributes of the storage devices, the method of managing data in the location management unit, the method of billing a user for the storage of data, and so forth.
On the other hand, there exists a business called a Storage Service Provider (SSP). The SSP provides a storage fitted for each customer""s request as an outsourcing. By entrusting the management of the storage onto the SSP, the customer enables to reduce the cost on preserving and managing the storage. The SSP needs to not only manage the storage volume but also respond to the performance, the reliability, the cost and the endurance to failure requested by each customer. Further, the SSP itself needs to keep the performance and the reliability as well as reduce the cost on preserving and managing the storage.
It is an object of the present invention to provide a method of preserving data by considering an attribute (performance or cost), an operation ratio, and a access frequency of data in a storage area network composing a plurality of storages having respective attributes, the method implemented by a business aspect such as a storage service provider.
In carrying out the foregoing object, the information processing system according to the present invention includes a location management unit for managing a location of data stored in a storage device (that will be basically referred simply to as a storage), an information duplication unit for duplicating data from one storage to another, and an attribute preservation unit for preserving attribute information for representing an attribute of each storage. This attribute preservation unit may be provided in each storage. Based on the attribute information preserved in this attribute preservation unit, the location management unit performs location management for writing and reading data.
Further, the location management unit preserves two or more pieces of location information of data corresponding to a file name (data identifier for indicting where the information is located) given from a computer. This makes it possible to preserve a plurality of data units in different storages with respect to one file name.
Further, an operation ratio is also provided for measuring an operation ratio of the storage. The location management unit performs the location management of the data to be written, the location management of the written data, and the location management of the data to be read out on the basis of this operation ratio. This operation ratio measurement unit may be provided in each storage.
Moreover, the location management unit preserves the access frequency of the data and the control information thereof (rules of data duplication and data movement set by a user) corresponding with the file name given from the computer. The control information may be set on each data unit by the computer. It may be pre-set by the location management unit.
Moreover, the location management unit preserves the movement and duplication histories of the data in correspondence with the file name given from the computer. Further, it preserves the price information in the attribute preservation unit. This makes it possible for the location management unit to duplicate and move the data from one storage to another through the use of the data duplication unit, based on the operation ratio of the storage, the access frequency of the data, the control information, or the price information.
Moreover, the location management unit preserves a group ID of the data in correspondence with the file name given from the computer. The location management unit performs the duplication and the movement of the data on the basis of the group ID.
In addition, the computer provides a data acceptance unit for accepting data to be transferred from the information duplication unit and a storage for storing the accepted data.